Science·Space Exploration·conceptual
Finding Exoplanets
Describe how astronomers detect planets around other stars using transit photometry (dip in starlight as a planet crosses) and radial velocity (Doppler wobble of the star), explain the habitable zone concept, and discuss what atmospheric biosignatures — such as oxygen, methane, and water vapour detected together — would suggest about a planet
Suggested ages 11–13
Evidence of understanding
- Explains transit photometry: the small, periodic dip in a star's brightness when a planet passes in front of it
- Explains the habitable zone as the range of distances from a star where liquid water could exist on a planet's surface
- Describes two or more atmospheric biosignatures and explains why their co-presence is significant (e.g. oxygen + methane together suggests active life replenishing both)
Assessment prompt
If Finding Exoplanets heard that a planet the size of Earth had been found in the habitable zone of a nearby star, could they explain how astronomers detected it, what the habitable zone means, and what they'd look for in its atmosphere to decide if life might exist there?
Standards alignment
No external standards are linked to this topic.